Degradation of polycyclic aromatic hydrocarbons by manganese peroxidase of Nematoloma frowardii

The degradation of polycyclic aromatic hydrocarbons by a manganese peroxidase crude preparation of Nematoloma forwardii was demonstrated for a mixture of eight different polycyclic aromatic hydrocarbons, and the five individual polycyclic aromatic hydrocarbons phenanthrene, anthracene, pyrene, fluoranthene, and benzo[alpha]pyrene. Oxidation of polycyclic aromatic hydrocarbons was enhanced by the addition of glutathione, a mediator substance, able to form reactive thiyl radicals. Glutathione-mediated manganese peroxidase (1.96 U ml(-1)) was capable of mineralizing [14C]pyrene (7.3%),[14C]anthracene (4.7%), [14C]benzo[alpha]pyrene (4.0%), [14C]benz(alpha)anthracene 2.9%), and [14C]phenanthrene (2.5%) in a period of 168 h. This is the first description of direct enzymatic mineralization of polycyclic aromatic hydrocarbons by manganese peroxidase, and indicates their important role in the oxidation of polycyclic aromatic hydrocarbons by wood-decaying fungi.